Abstract
Background. Carbapenem-resistant Gram-negative bacteria (CR-GNB), particularly metallo-β-lactamase (MBL) producers, are WHO critical-priority pathogens. In Libya, laboratory-based data are scarce, and no study has assessed endemic medicinal plants as adjunctive options. Objectives. To generate baseline data on carbapenem resistance and MBL production among clinical Gram-negative pathogens in Misurata, Libya, and to preliminarily evaluate the antibacterial activity and phytochemical composition of Arbutus pavarii extracts. Methods. We conducted a cross-sectional study of 244 non-duplicate clinical isolates. Carbapenem susceptibility was determined by Kirby-Bauer disc diffusion; MBL production was confirmed by double-disc synergy and combined-disc tests. Ethanolic and aqueous extracts from A. pavarii leaves, stems and fruits were tested against resistant isolates by disc diffusion. Phytochemicals were profiled by HPLC. Results. The predominant carbapenem-resistant species were Acinetobacter baumannii (29.5%), Klebsiella pneumoniae (26.2%) and Pseudomonas aeruginosa (19.7%). Resistance to both imipenem and meropenem exceeded 60% across these isolates, and MBL activity was detected in 54.5% of carbapenem-resistant K. pneumoniae. Among plant extracts, the aqueous leaf extract showed the highest antibacterial activity against MBL-producing isolates (mean inhibition zone 9.46±7.61 mm at 100%), slightly exceeding the corresponding ethanolic extract (9.31±7.30 mm). Both extracts demonstrated concentration-dependent effects (P<0.05; ANOVA/Kruskal-Wallis). HPLC analysis identified catechin and quercetin as major components, which may underlie the observed activity. Conclusions. This first laboratory-based report from Libya documents high rates of CR-GNB and MBL production and introduces A. pavarii as a promising endemic plant with adjunctive antibacterial potential. Findings support enhanced AMR surveillance and the exploration of resource-sensitive alternatives in African healthcare settings.